I am able to do the hand signs for Marfan syndrome but wasn't diagnosed yet, can I just look like a marfan?

In brief:
Doctors can evaluate

A person with a few of the marfan syndrome features can see a primary care doctor and a geneticist.

The geneticist specializes in diagnosing genetic disorders such as marfan syndrome. A person has to have a certain number of signs & symptoms before he is diagnosed as marfan syndrome. If less than the minimum signs & symptoms, he may have marfanoid habitus (appearance) but not have marfan syndrome.

In brief:
Doctors can evaluate

A person with a few of the marfan syndrome features can see a primary care doctor and a geneticist.

The geneticist specializes in diagnosing genetic disorders such as marfan syndrome. A person has to have a certain number of signs & symptoms before he is diagnosed as marfan syndrome. If less than the minimum signs & symptoms, he may have marfanoid habitus (appearance) but not have marfan syndrome.
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In brief:
Joint hypermobility

Joint hypermobility is only one of the symptoms that is used to diagnose marfan syndrome (along with reduced upper to lower body segment ratio, longer arm span than height, dislocated lens in the eye, among others).

Joint hypermobility can occur in otherwise healthy individuals and should be managed with muscle strengthening and other exercises to protect the joints.

In brief:
Joint hypermobility

Joint hypermobility is only one of the symptoms that is used to diagnose marfan syndrome (along with reduced upper to lower body segment ratio, longer arm span than height, dislocated lens in the eye, among others).

Joint hypermobility can occur in otherwise healthy individuals and should be managed with muscle strengthening and other exercises to protect the joints.
Would you like to video or text chat with me?